Effect Of Mechanical Injury Research Articles

P-450 Mechanical injury improves follicle survival in xenotransplanted human ovarian cortex

Abstract Study question Can mechanical injury by needle puncturing of frozen thawed human ovarian cortex tissue prior to transplantation increase revascularization of xenografts and improve follicle survival? Summary answer Mechanical injury caused by needle puncture prior to transplantation improved follicle survival 2-fold in human ovarian cortex tissue after 4 weeks xenografting. What is known already Cryopreservation and autotransplantation of ovarian tissue is an established fertility preservation method which has resulted in numerous live births worldwide. However, the efficiency of the method is hampered by a critical follicle loss after transplantation. Faster revascularization of the transplanted graft would shorten the ischemic period and could potentially improve follicle survival. Controlled tissue damage by laser or needles can induce local angiogenesis by initiating the wound healing mechanisms and has been applied clinically in cardiovascular surgery for decades. Whether controlled mechanical tissue damage could be used to improve grafting of human ovarian cortex tissue has not yet been investigated. Study design, size, duration A total of 32 frozen-thawed human ovarian cortex pieces were cut in halves; one half serving as the untreated control and the other half was punctured approximately 200 times with a 29G needle immediately after thawing. The cortical pieces were transplanted subcutaneously to 10 immunodeficient mice. Ovarian grafts were retrieved after 3, 6 and 10 days (n = 8) to analyse graft revascularization and gene expression, and after 4 weeks to assess follicle density (n = 8). Participants/materials, setting, methods Ovarian cortex was donated by 16 women (aged 24-36 years) undergoing ovarian tissue cryopreservation for fertility preservation at a University Hospital. Gene expression analysis of proinflammatory cytokines (Tnf-α), apoptotic factors (Bcl2 and Bax), and angiogenic factors (Vegfa, Angptl4, Ang1, and Ang2) were performed by qPCR. Follicle density after 4 weeks xenografting were evaluated histologically. Graft-revascularization was assessed using immunohistochemical detection of murine Cd31. Main results and the role of chance Our results showed that the ovarian grafts which had been punctured with needles prior to transplantation contained a larger number of surviving follicles per mm3 compared to the untreated control (control group: 2.9 ± 0.6 (mean±SEM) follicles/mm3; needle group: 6.4 ± 2.4 follicles/mm3). Follicle densities between patients and groups varied from 0.8 to 26 follicles/mm3. Overall, a 2.3-fold increase in follicle density was found in the needle group compared to control, though this finding was not significantly different (p-value = 0.1182). The relative gene expression of Tnf-α and the Bax/Bcl2 ratio after 6 days grafting was similar in the needle and control group, indicating that the mechanical injury did not induce an additional inflammatory or apoptotic response in the grafts. The relative gene expression of Vegf, Angptl4, and Ang2 after 6 days grafting was highest in the needle group compared to the control group, though not significant (p>0.1). Results of the gene expression analysis from Day 3 and 10 are awaited, and so are the quantification of the Cd31 positive vessel area and vascular density from Day 3, 6, and 10, which will provide valuable insight into the initial graft revascularization. Limitations, reasons for caution The ovarian follicles are highly heterogeneously distributed in the ovarian cortex and can vary 100-fold between cortex pieces from the same woman and between patients. A high variability in follicle density within and between treatment groups and patients was found in the current study. Thus, solid conclusions cannot be made. Wider implications of the findings Our findings suggest a positive effect of mechanical injury on human ovarian grafts as needle puncturing prior to transplantation improved follicle survival after xenotransplantation. Clinically, this technique would be easy to implement since it is performed during the thawing process and does not involve any additional treatment of the patient. Trial registration number Not applicable

Anatomical and Biochemical Traits Associated with Field Resistance of Onion Cultivars to Onion Thrips and the Effect of Mechanical Injury on the Level of Biochemical Compounds in Onion Leaves

Thrips tabaci Lind. is a global pest and also represents a serious threat to onion production in Poland. In 2 years (2015–2016) of field studies, 8 onion cultivars were evaluated to characterize the resistance to onion thrips and to determine if any biochemical and anatomical features of onion plants are associated with antixenotic and/or antibiotic mechanisms of resistance. Additionally, the influence of mechanical injury on the content of several biochemical compounds in onion leaves was made. The resistance to thrips colonization during the migration period, abundance, and thrips damage throughout the whole vegetation season was determined. We identified two cultivars, Tęcza and Wenta, resistant to thrips colonization and abundance, and one cultivar Wenta resistant to thrips damage. A positive correlation between concentrations of the reducing sugars and thrips abundance and conversely negative relationships between the total phenolic content and thrips damage was confirmed in both years. We suspect that a thinner epidermal layer, a smaller area of epidermal and mesophilic cells, and a lower diameter of vascular bundles may favor the resistance of onion cultivars to thrips. Thrips foraging resulted in a decrease in the content of soluble sugars, sucrose, and plant pigments in the leaves of all onion varieties.

Effect of mechanical injury and IL-1β on the expression of LOXs and MMP-1, 2, 3 in PCL fibroblasts after co-culture with synoviocytes

BackgroundCrosstalk between posterior cruciate ligament fibroblasts (PCLfs) and synoviocytes (SCs) significantly modifies the homeostatic balance of the extracellular matrix (ECM) and appears to post a prominent affection for wound healing of PCL. Interleukin-1β (IL-1β) is regarded as a critical factor in acute inflammatory events during ligament injury. MethodsIn order to confirm the capability of SCs the response of lysyl oxidases (LOXs) and matrix metalloproteinases (MMPs) to IL-1β, the complex cues of the joint cavity following PCL injury were simulated and the effect of IL-1β on the expression of LOXs and MMPs in PCLfs were investigated. PCLfs in both the mono- and co-culture conditions were treated with IL-1β. Cell lysates were collected from the PCLfs and LOXs and MMP-1, 2, 3 expression quantified using quantitative real-time PCR and western bolting. ResultsThe results indicated that injury alone elevated the expression of LOXs and MMP-1, 2 and 3. But IL-1β significantly decreased the LOX, LOXL1, and LOXL3 expression, and simultaneously increased MMP-1, 2 and 3 expressions in injured PCLfs. Furthermore, co-culture further suppressed LOXs, but stimulated MMP-1, 2 and 3 expressions when subjected to both mechanical injury and IL-1β treatment. This possibly suggests that a number of soluble factors are secreted that act as mediators that amplify the response of SCs. ConclusionThe results indicated that the SCs could affect the IL-1β-induction of LOXs inhibition and MMPs accumulation, which may be the underlying mechanism of the the poor healing response following PCL injury.

Effects of mechanical Injury, cotyledon elimination and nutrition for the germination of apple seeds (Malus pulmila var. domestica)

Effects of mechanical Injury, cotyledon elimination and nutrition for the germination of apple seeds (<i>Malus pulmila</i> var. <i>domestica</i>)

Effects of mechanical injury on the tribological rehydration and lubrication of articular cartilage

Healthy articular cartilage is crucial to joint function, as it provides the low friction and load bearing surface necessary for joint articulation. Nonetheless, joint injury places patients at increased risk of experiencing both accelerated cartilage degeneration and wear, and joint dysfunction due to post-traumatic osteoarthritis (PTOA). In this study, we used our ex vivo convergent stationary contact area (cSCA) explant testing configuration to demonstrate that high-speed sliding of healthy tissues against glass could drive consistent and reproducible recovery of compression-induced cartilage deformation, through the mechanism of ‘tribological rehydration’. In contrast, the presence of physical cartilage damage, mimicking those injuries known to precipitate PTOA, could compromise tribological rehydration and the sliding-driven recovery of cartilage function. Full-thickness cartilage injuries (i.e. fissures and chondral defects) markedly suppressed sliding-driven tribological rehydration. In contrast, impaction to cartilage, which caused surface associated damage, had little effect on the immediate tribomechanical response of explants to sliding (deformation/strain, tribological rehydration, and friction/lubricity). By leveraging the unique ability of the cSCA configuration to support tribological rehydration, this study permitted the first direct ex vivo investigation of injury-dependent strain and friction outcomes in cartilage under testing conditions that replicate and maintain physiologically-relevant levels of fluid load support and frictional outcomes under high sliding speeds (80 mm/s) and moderate compressive stresses (~0.3 MPa). Understanding how injury alters cartilage tribomechanics during sliding sheds light on mechanisms by which cartilage's long-term resilience and low frictional properties are maintained, and can guide studies investigating the functional consequences of physical injury and joint articulation on cartilage health, disease, and rehabilitation.

Effects of mechanical injury and insect feeding on volatiles emitted by wheat plants

We report on changes in the volatiles emitted by wheat plants of the cultivar ‘Tonacja’ after the plants were scraped, pierced or damaged by adults of Oulema melanopus (Linnaeus). The blend of volatiles was dominated by typical green leaf volatiles and in addition contained linalool and B-caryophyllene, but the latter two were released in large amounts only after more than one day of insect feeding. Overall, the plants that had been damaged by the insect released more odors than the plants that were subjected to mechanical damage. Moreover, control plants released significantly lower amounts of volatiles. Scraping of leaves induced higher volatile emission than puncturing the leaves. A Y-tube bioassay was used to evaluate upwind orientation ofadult cereal leafbeetles. Greater number of female 0. melanopus was attracted to (Z)-3-hexenal and (Z)-3 -hexenyl acetate at low concentrations. Higher concentration of these compounds and linalool significantly repelled both females and males.

Solute Transport of Negatively Charged Contrast Agents Across Articular Surface of Injured Cartilage.

Solute transport through the extracellular matrix (ECM) is crucial to chondrocyte metabolism. Cartilage injury affects solute transport in cartilage due to alterations in ECM structure and solute-matrix interactions. Therefore, cartilage injury may be detected by using contrast agent-based clinical imaging. In the present study, effects of mechanical injury on transport of negatively charged contrast agents in cartilage were characterized. Using cartilage plugs injured by mechanical compression protocol, effective partition coefficients and diffusion fluxes of iodine- and gadolinium-based contrast agents were measured using high resolution microCT imaging. For all contrast agents studied, effective diffusion fluxes increased significantly, particularly at early times during the diffusion process (38 and 33% increase after 4min, P<0.05 for iodine and Gd-DTPA; and 76% increase after 10min for diatrizoate, P<0.05). Effective partition coefficients were unaffected in mechanically injured cartilage. Mechanical injury reduced PG content and collagen integrity in cartilage superficial zone. This study suggests that alterations in contrast agent diffusion flux, a non-equilibrium transport parameter, provides a more sensitive indicator for assessment of cartilage matrix integrity than partition coefficient and the equilibrium distribution of solute. These findings may help in developing clinical methods of contrast agent-based imaging to detect cartilage injury.

Utilização da microscopia eletrônica de varredura como ferramenta de avaliação da estrutura do tecido de abacate 'quintal' após danos mecânicos

Avaliaram-se os efeitos de injúrias mecânicas, por impacto, compressão e corte nas estruturas celulares de abacates 'Quintal'. Na injúria por impacto, eles foram deixados cair, em queda livre, de uma altura de 2,00 m, sobre os lados opostos, de sua região equatorial; na compressão, foram colocados sob um peso de 117,6 N, por 24 horas, o que provocou duas lesões opostas, no sentido longitudinal; e os cortes foram aplicados em número de quatro, longitudinalmente, com 40 mm de comprimento e 4 mm de profundidade, nos lados opostos dos frutos. Após 5 dias de armazenamento, sob condições de ambiente (25ºC e 60% UR), procedeu-se à verificação das estruturas celulares através de microscopia eletrônica de varredura. A microscopia eletrônica de varredura indicou que os abacates injuriados por compressão e impacto, embora sem lesões aparentemente visíveis, apresentavam desordem celular em suas estruturas.

Effect of Mechanical Injury and Low Temperature Storage on the Accumulation of Glycoalkaloids in the Tubers of 7 Varieties of Potato (Solanum Tuberosum L.) grown in Oman

Tubers from 7 potato varieties were analyzed for their rates of glycoalkaloid accumulation in response to stresses of three types of mechanical injury and low temperature storage. Mechanical injuries were found to greatly stimulate glycoalkaloid accumulation in both peel and flesh of tubers. The extent of glycoalkaloid accumulation appears to depend on variety, type of mechanical injury, and storage period. Most of the injury-stimulated glycoalkaloid accumulation occurred within 7 and 14 days after treatment. Cutting the tubers resulted in the highest content of glycoalkaloids both in flesh and peel up to levels that exceeded the upper safety limit of 200 mg/kg FW. Injury stimulated α-solanine accumulation in stored potato tubers is more than α-chaconine, resulting in a decrease in the α-chaconine: α-solanine ratio. When tubers were stored at low temperature, the rate of glycoalkaloid accumulation was found to be independent of the glycoalkaloid level at harvest. The greatest increase in total glycoalkaloid content of the seven varieties was found after two weeks of storage at both 4 ºC and 10 ºC. Further storage at these temperatures resulted in a decrease in the rate of glycoalkaloid accumulation in most of them. At 10 ºC glycoalkaloid content tended to increase more rapidly than at 4 ºC. The α-solanine content of the tubers showed an increase following low temperature storage.

Dark hair cells in the inner ear of the rainbow trout. A study of the influence of different fixation methods

AbstractThe occurrence of dark staining cells in different tissues has been suggested to be artefactual and caused during the fixation process. In inner ear sensory epithelia, dark hair cells (DHC) have been suggested to be apoptotic cells. We have examined whether dark cells represent dying cells or whether they are the results of fixation artefacts. The effects of buffer osmolarity and different fixation methods on the incidence of dark hair cells in the inner ear macula sacculi of the rainbow trout (Oncorhynchus mykiss) were investigated by light and electron microscopy. Glutaraldehyde in phosphate buffer with osmolarities of 0, 135, 225, 425, and 560 mosmol were used for fixation by immersion. For comparison, fixation by vascular perfusion as well as the effects of mechanical injury and delayed fixation were studied. DHC were found in all examined saccular maculae except for the delayed fixation protocol where almost all the sensory cells were lost. The number of DHC accounted for 2.5–12.9‰ of the sensory cells. Neither the buffer osmolarity nor the fixation method had significant effects on the frequencies of DHC. Mitotic cell division events were seen exclusively in the apical cell strata of the sensory epithelium. The DHC are suggested to be associated with apoptosis rather than fixation artefacts.

Effects of injurious compression on matrix turnover around individual cells in calf articular cartilage explants.

The effects of mechanical injury on the metabolism of cartilage matrix are of interest for understanding the pathogenesis of osteoarthrosis and the development of strategies for cartilage repair. The purpose of the present study was to examine the effects of injury on matrix turnover in a calf articular cartilage explant system for which the effects of mechanical loading on cell activity and the cell-mediated pathways of matrix metabolism are already well characterized. New methods of quantitative autoradiography were used in combination with established biochemical and biomechanical techniques for the analysis of cell and matrix responses to acute mechanical injury, with particular attention to the processes of localized matrix turnover in the cell-associated matrices of individual chondrocytes. Matrix deposition and turnover around cells in control explants was spatially dependent, with the highest rates of proteoglycan deposition and turnover and the lowest rates of collagen deposition (as indicated by [3H]proline autoradiography) occurring in the pericellular matrix. Injurious compression was associated with (a) an abrupt decrease in the tensile load-carrying capacity of the collagen matrix, apparently associated with mechanical failure of the tissue, (b) a considerable but subtotal decrease in cell viability, marked by the emergence of an apparently inactive cell population interspersed within catabolically active but abnormally large cells, and (c) sustained, elevated rates of proteoglycan turnover, particularly in the cell-associated matrices of apparently viable cells, which involved the increased release of aggregating species in addition to a spectrum of degradation fragments that were also in controls. These results may represent an in vitro model for the responses of chondrocytes and the cartilage extracellular matrix to mechanical injury.

Reduction of voltage-dependent Mg2+ blockade of NMDA current in mechanically injured neurons.

Activation of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors is implicated in the pathophysiology of traumatic brain injury. Here, the effects of mechanical injury on the voltage-dependent magnesium (Mg2+) block of NMDA currents in cultured rat cortical neurons were examined. Stretch-induced injury was found to reduce the Mg2+ blockade, resulting in significantly larger ionic currents and increases in intracellular free calcium (Ca2+) concentration after NMDA stimulation of injured neurons. The Mg2+ blockade was partially restored by increased extracellular Mg2+ concentration or by pretreatment with the protein kinase C inhibitor calphostin C. These findings could account for the secondary pathological changes associated with traumatic brain injury.

RELATIONSHIP BETWEEN DAMAGE INDEX AND HEIGHT LOSS OF POTATOES DURING STORAGE

Abstract The effect of mechanical injury of potatoes as expressed by the damage index on weight loss during storage was investigated during a three-year study. The damage index is an internationally accepted categorization of the magnitude of injury inflicted on potatoes during harvesting and handling. Weight loss from potatoes in storage was found to be significantly correlated to the damage index. Damage free potatoes had significantly less weight loss than those with injury.

Neuronal sprouting and synapse formation in response to injury in the mouse organ of corti in culture

The effect of mechanical injury on induction of regenerative phenomena within the neurosensory epithelium was investigated in cultures of neonatal mouse cochlea. The oldest examined culture in which new neuronal growth followed insult, was injured at 13 days in vitro and fixed 24 h later. By far, the most vigorous regenerative reaction was observed in a 3-day culture 4 h post-injury. The reaction included sprouting of nerve fibers injured directly, synapse formation between the surviving hair cells and sprouting neuronal growth cones, wrapping of growing nerve fibers by extending processes of hair cell cytoplasm, and collateral sprouting of synaptically-engaged nerve endings and of nerve fibers in passage.

The effect of blunt trauma on the ultrastructure of ratellar chondrocytes in rabbit articular cartilage a light and electron microscopic study

In order to determine the effects of mechanical injury upon articular cartilage, we caused trauma by a direct blow of 750 gr. weight on the flexed knees of rabbits. The joints were examined by light and electron microscopy at two intervals after the injury. In all specimens significant changes were observed in the cytoplasm of the chondrocytes. In addition, quantitative observations are reported to measure the observed degenerated ultrastructural changes.

Seed Dormancy in Avena fatua. III. The Effect of Mechanical Injury on the Growth and Development of the Root and Scutellum

When dormant, imbibed caryopses of Avena fatua L. were induced to germinate by piercing a hole in the seed coat (pericarp plus aleurone layer), the rate of germination and the pattern of embryo development were both related to the site of injury. Piercing the dormant caryopsis 1 mm from the radicle end induced emergence of the radicle within 24-36 h and prior to any growth response of the scutellum. This germination behavior was similar to that of intact, nondormant (afterripened) caryopses, which served as controls. When dormant caryopses were pierced on the abaxial surface 5 mm from the proximal end and 1 mm distal to the tip of the scutellum, elongation of the scutellum was initiated after 48-72 h and was associated with papillae formation, xylem differentiation, and cell division in the distal region of the scutellum. These scutellar responses preceded elongation of the radicle by ca. 24 h. The restricted distribution of the response to piercing and the ability of this treatment to initiate the resump...

Effect of Mechanical Injury on the Ascorbic Acid Content of Potatoes

ABSTRACTEffects of two types of mechanical injury (wounding and bruising) on the ascorbic acid content of Belrus cultivar tubers were compared. Wounding involved cutting slices (1 mm) and strips (10 × 20 mm) and both slices and strips exhibited a highly significant increase (p &lt; 0.01) in ascorbic acid following wounding. The largest increase (400%) occurred in slices after 2 days. Ascorbic acid decreased significantly (p &lt; 0.05) in the bruised halves as compared with the unbruised halves. Maximum decrease in ascorbic acid (347%) of bruised tissue occurred after 2 days storage at 5°C. The unbruised halves appeared to synthesize ascorbic acid when compared with the controls, the maximum increase (144%) occurring after 2 days storage at 5°C.

The effect of mechanical injury on exudation from immature and mature peanut fruits under axenic conditions

Sugars and amino-N compounds exuded from axenically-grown peanut fruits following mechanical injury, were measured by gas-liquid and thin-layer chromatography. Injury of the peanut fruit surface resulted in a 10–20 fold increase in sugar exudation and an increase in the amount of amino N exuded. Analysis of leachates of the weblite (an exploded shale soil substitute) in which axenic fruits developed showed that exudation of sugars had occurred from uninjured fruits in situ. These results support the hypothesis that exudates in the geocarposphere are an important ecological factor affecting microbes in the soil and the colonization of peanut fruits by Aspergillus flarus.

Effect of mechanical injury to bone marrow in irradiated mice on dispersion of endogenous colony-forming units

The femur was fractured in mice irradiated in a dose of 600 R and the fragments united by a metal pin. Under these conditions, when part of the bone marrow was destroyed, the number of endogenous colonies in the spleen was increased.

Effects of Mechanical Injury, Fungi, and Soil Temperature on Peanut Seed Decay in Soil

Effects of Mechanical Injury, Fungi, and Soil Temperature on Peanut Seed Decay in Soil